Sensory Function Flashcards
The point at which pain is perceived
Pain threshold
The amount of pain that an individual can physically and emotionally withstand
Pain tolerance
One of two types of pain the body perceives. It results from noxious stimuli to the skin, joints, muscles, and tendons. These stimuli may include cutting, crushing, pinching, extreme temperature, and irritating chemicals. Generally easy to pinpoint
Somatic pain
One of the two types of pain the body perceives. It results from noxious stimuli to internal organs and may include expansion and hypoxia. Is usually vague and diffuse. It may even be sensed on body surfaces at distant locations from the originating organ
Visceral pain
Pain at distant locations from the originating site
Referred pain
Pain that exists after the removal of a body part. The affected person may feel the discomfort of the removed part. The severing of neurons may result in spontaneous firing of spinal cord neurons because normal sensory input has been lost. This type of pain can be very distressing but usually resolves in time
Phantom pain
Chronically progressing pain that is unrelenting and severely debilitating. This type of pain does not usually respond well to typical pharmacologic pain treatments. Is common with severe injuries, especially crushing injuries
Intractable pain
Pain that results from damage to peripheral nerves by disease or injury. This type of pain tends to be chronic and intractable
Neuropathic pain
Rapid, involuntary back-and-forth eye movement
Nystagmus
The absence of the auricle
Anotia
An underdeveloped small auricle
Microtia
A condition in which a body passage is closed or missing. It includes lack of the valve opening in the heart to allow blood flow (pulmonary atresia) and lack of an external ear canal (aural atresia)
Atresia
Loss of hearing that can occur because of damage associated with maternal rubella and syphilis infection during pregnancy
Congenital hearing loss
Difficulty focusing the eyes resulting from age-related changes
Presbyopia
Age-related hearing loss
Presbycusis
An infection or inflammation of the conjunctiva, the lining of the eyelids and sclera
Conjunctivitis
An inflammation of the cornea that can be triggered by an infection or trauma
Keratitis
An infection or inflammation of the middle ear
Acute Otitis media (AOM)
An infection or inflammation of the external ear canal or auricle. Also called swimmer’s ear
Otitis externa
Double vision
Diplopia
A group of eye conditions that lead to damage to the optic nerve. This damage is often caused by increased intraocular pressure but can also be caused by decreased blood flow to the optic nerve
Glaucoma
Type of glaucoma in which intraocular pressure increases gradually over an extended period. It is the most common type
Open-angle glaucoma
Type of glaucoma that results from a sudden blockage of aqueous humor outflow; it is a medical emergency
Closed-angle glaucoma
Type of glaucoma that is present at birth. It is a result of abnormal development of outflow channels (trabecular meshwork) of the eye
Congenital glaucoma
Type of glaucoma that is a result of certain medications, eye diseases, and systemic diseases
Secondary glaucoma
Opacity or clouding of the lens of the eye
Cataract
A deterioration of the macular area of the retina caused by impaired blood supply to the macula that results in cellular waste accumulation and ischemia
Macular degeneration
An abnormal bone growth in the middle ear, usually involving an imbalance in bone formation and resorption
Otosclerosis
A disorder of the inner ear that results from endolymph swelling, which stretches the membranes and interferes with the hair receptors in the cochlea and vestibule
Meniere disease
A gaze deviation of one eye. They eyes do not coordinate to focus on the same object together, resulting in diplopia. Also called cross-eyes
Strabismus
The loss of one eye’s ability to see details. The most common cause of vision problems in children. It occurs when the brain and eyes do not work together properly; the brain favors one eye. Also called lazy eye
Amblyopia
An acute condition in which the retina separates from its supporting structures
Retinal detachment
A persistent perception of abnormal noises in the ear, which may be described as ringing, buzzing, humming, whistling, roaring, or blowing
Tinnitus
An illusion of motion. People experiencing vertigo have a sensation that they or the room is spinning or moving
Vertigo
Also known as lazy eye
Weakness of the levator muscle
Unopposed action of the orbicularis oculi
Weakness of the orbicularis oculi causes an open eyelid
Ptosis
Turning in of the lid margin
Entropion
Eversion of the lower lid margin (concern of issues with dry eye)
Ectropion
Inflammation of the lacrimal sac
Most often from a blockage of the nasolacrimal duct
Dacryocystitis
Inflammation along the edges of the eyelids
Seborrheic form (usually associated with seborrhea (dandruff) of the scalp or brows
Staphylococcal blepharitis (may be caused by Staphylococcus epidermidis or S. aureus - the lesions are often ulcerative)
Blepharitis
Infection of the sebaceous glands of the eyelid and can be internal or external (also known as a stye)
Hordeolum
May follow an internal hordeolum
Chronic inflammatory granuloma of meibomian glands (a stye seen more on the inner eyelid)
Chalazion
Tear film protects and hydrates the surface of the eye
Deterioration/disruption of film caused by:
- Aging
- From loss of reflex lacrimal gland secretion
- Contact lenses
- Sjogren syndrome (inflammatory/autoimmune disease)
Treatment:
- Artificial tears
- Plug lacrimal puncta
- Ointments
Dry Eyes
This causes yellow, thick drainage
Causes include:
Bacterial
Viral
Chlamydial
Ophthalmia
Allergic type is usually clear, watery drainage
Chemosis (severe yellowing/allergic reaction)
Infectious/Allergic Conjunctivitis
Fleshy, vascular tissue that grows over the cornea (wing-like look)
Disorder of the Conjunctiva - Pterygium
Yellow, raised growth on the conjunctiva
Pinguecula
Corneal trauma (more severe)
Corneal edema
Corneal abrasion (less severe)
Fluorescent dye is used to wash away any debris
Disorders of the Cornea
Inflammation of the cornea
Causes:
- Trauma (UV light, welding, contact over-use)
- Viral (herpes, zoster, Epstein-Barr, cytomegalovirus)
Manifestations:
- Pain
- Erythema
- Drainage
- Photophobia (sensitivity to light)
- Visual disturbances
Keratitis
An accumulation of leukocytes within the anterior chamber (pus in the eye)
Results from severe intraocular inflammation
Hypopyon
Infection and inflammation of the tissue and skin surrounding the eye
Periorbital Cellulitis
Infection and inflammation of the anterior portion of the eyelid (more serious as it gets closer to the eye)
Similar to other soft tissue/skin cellulitis
Treat with antibiotics
Preseptal Cellulitis
Infection and inflammation of the globe
Often involves fat and extracellular muscles
Watch for signs of pain with eye movement
Much more urgent than periorbital cellulitis
Requires immediate ophthalmology referral and often hospitalization
Usually caused by bacterial infection or scratch or trauma
Orbital Cellulitis
Subconjunctival hemorrhage (may be spontaneous)
Traumatic iritis
Hyphema (after trauma to the eye blood pools in the eye - emergency)
Orbital blow out fractures
Eye trauma
Controls the size of the pupil
- Is controlled by the autonomic nervous system
Alterations include:
- Damage to CN III
- Opiate usage
- Miotic drugs
Pupillary Reflex
Which system controls pupillary constriction?
Parasympathetic nervous system
Which system controls pupillary dilation?
Sympathetic nervous system
This serves to main the intraocular pressure
- Provides for the nutritive needs of the lens and posterior cornea
- Mediates the exchange of respiratory gases
- Contains a low concentration of protein and high concentrations of ascorbic acid, glucose, and amino acids
The aqueous humor
An optic neuropathy characterized by optic disk cupping and visual field loss
Causes:
- An increase in intraocular pressure that results from abnormalities in the balance between aqueous production and outflow
- Most common cause is an interference with aqueous chamber, rather overproduction of the aqueous humor
Glaucoma
This classification of glaucoma depends on the location, circulation, and reabsorption
Angle-closure (narrow-angle) versus open-angle (wide-angle)
This type of glaucoma is characterized by no evidence or preexisting ocular or systemic diseaes
Primary glaucoma
This type of glaucoma is the result of inflammatory processes affecting the eye, tumors, or blood cells of trauma-produced hemorrhage
Secondary glaucoma
- Excessive lacrimation and photophobia
- Affected infants tend to be fussy, have poor eating habits, and rub their eyes frequenly
- Diffuse edema of the cornea usually gives the eye a grayish white appearance
- Enlargement of the entire optic globe (buphthalmos)
Symptoms of Congenital or Infantile Glaucoma
A vision problem where nearby objects look blurred, while distant objects are more clearly visible.
- The anterior-posterior dimension of the eyeball is too short; the image is focused posterior to (behind) the retina
Hyperopia or Farsightedness
A condition in which on can see near objects, but cannot see far objects clearly.
- The anterior-posterior dimension of the eyeball is too long; the focus point for an infinitely distant target is anterior to the retina
Myopia or Nearsightedness
Refers to changes in vision that occur because of aging.
Presbyopia
Lens opacity that interferes with the transmission of light to the retina
- the most common cause of age-related visual loss in the world
Causes are multifactorial:
- Effects of aging, genetic influences, environmental and metabolic influences, drugs, and injury
- Diabetes
- Long-term exposure to sunlight
- Heavy smoking
- Developmental defect
- Secondary to trauma or diseases
Surgery is the only treatment for correcting vision loss: intraocular lens implantation
Cataract
Capable of black-white discrimination
Rods
Capable of color discrimination
Cones
A group of rare, genetic disorders that involve a breakdown and loss of cells in the retina - which is the light sensitive tissue that lines the back of the eye.
Common symptoms:
- Difficulty seeing at night
- Loss of side (peripheral) vision
- Slow degenerative changes in the retinal photoreceptors
- Autosomal and sex-linked forms
- Night blindness
- Bilateral symmetric loss of mid-peripheral fields
- Visual field defects gradually increase both centrally and peripherally
- Cone photoreceptor cells are also affected, and day vision and central visual acuity are compromised
Retinitis Pigmentosa
Entrance and exit of the central artery and vein of the retina through the tough scleral tissue at the optic papilla
May be compromised by an condition causing persistent increased intracranial pressure
- Cerebral tumors, subdural hematomas, hydrocephalus, and malignant hypertension
Results in the destruction of the optic nerve axons
Papilledema
Nonproliferative-confined to the retina
- Engorgement of the retinal veins, thickening of the capillary endothelial basement membrane, and development of capillary microaneurysms
- Macular edema
Proliferative-characterized by formation of new fragile blood vessels
- Bleed easily
- Retinal detachment
Diabetic Retinopathy
Separation of the neurosensory retina from the pigment epithelium
- Exudative: accumulation of fluid in the subretinal space
- Traction: scar tissue
- The vitreous begins to liquefy and collapse: most common type
Retinal detachment
Degenerative changes in the central portion of the retina (the macula) that results primarily in the loss of central vision - point where there is the most rods and cones
Dry form:
- An atrophic nonexudative
- Blood vessels become thin and brittle
- Drusen forms, blurring vision
Wet form:
- Exudative: fluid build up
Macular Degeneration
Blindness in one eye
Anopia
Half of the visual field for one eye is lost
Hemianopia
Quarter of the visual field is lost for one eye
Quadrantanopia
The loss of different half-fields in the two eyes
Heteronymous hemianopia
Bilateral loss of the entire primary visual cortex
Corical blindness
Extensive damage to the visual association cortex that surrounds an intact primary visual cortex results in a loss of the learned meaningfulness of visual images
Visual agnosia
A condition of diminished vision in which no detectable organic lesion of the eye is present
Amblyopia
An abnormality of eye coordination or alignment that results in loss of binocular vision
- Paralytic
- Nonparalytic
Strabismus
The formation of new spongy bone around the stapes and oval window, which results in progressive deafness
Bone increasingly immobilizes the stapes, reducing the transmission of sound
Pressure on middle ear structures or the vestibulocochlear nerve may contribute to the development of tinnitus, sensorineural hearing loss, and vertigo
Otosclerosis
The perception of abnormal ear or head noises, not produced by an external stimulus
Tinnitus
Stimuli are not adequately transmitted - sound doesn’t reach cochlear
Conductive hearing loss
Disorders that affect the inner ear, auditory nerve, or auditory pathways of the brain
Sensorineural hearing loss
Sudden onset of dizziness or vertigo that is provoked by certain changes in head position
Benign paroxysmal positional vertigo
Fluctuating episodes of tinnitus, feelings of ear fullness, and violent rotary vertigo that often renders the person unable to sit or walk
Causes include:
- Trauma
- Infection
- Immunologic
- Endocrine (adrenal-pituitary insufficiency and hypothyroidism)
- Vascular disorders have been proposed as possible causes
Meniere’s disease
Loss of smell
Anosmia
Loss of taste
Ageusia
Causes of this include:
- CNS lesions involving the cerebellum and lower brain stem
- Brain stem ischemia
- Tumors
- Multiple sclerosis
Vertigo
